Uniform-irradiance extended-source freeforms

Abstract

A lighting apparatus for providing uniform irradiance is provided. The lighting apparatus includes a light source configured to emit rays toward a polygonal target region, and a lens configured to uniformize irradiance from the light source to the target region, wherein sag of the lens and normals along a boundary of the lens are arranged so as to illuminate a perimeter of the target region based on an edge-ray mapping, wherein a lens surface is formed based on polyharmonic spline interpolations so as to smoothly illuminate an interior of the target region, wherein the irradiance is uniformized by argumenting light field tailoring of the lens, wherein the light field tailoring is augmented to maintain to maintain the irradiance perimeter.

The invention claimed is: 
     
       1. A lighting apparatus for providing uniform-irradiance to a target region, comprising:
 an extended light source configured to emit rays; 
 a lens configured to receive and uniformize irradiance of the rays from the light source to the target region, wherein sag of the lens and normals along a boundary of the lens are arranged so as to illuminate a perimeter of the target region based on an edge-ray mapping, wherein a lens surface is interpolated from the boundary of the lens to illuminate an interior of the target region, wherein the lens surface is tailored so that light field of the rays thru the lens uniformly irradiates the interior and perimeter of the target region, wherein spill of the light field outside the perimeter of the target region is controlled. 
 
     
     
       2. The lighting apparatus of  claim 1 , wherein the light source is embedded in the lens. 
     
     
       3. The lighting apparatus of  claim 1 , wherein the target region is represented by a convex polygon. 
     
     
       4. The lighting apparatus of  claim 1 , wherein the edge-ray mapping is performed such that rays from edges of the light source are routed through opposite edges of the lens and assigned to point on edges of the target region. 
     
     
       5. The lighting apparatus of  claim 3 , wherein the target polygon is a regular or irregular convex polygon deformed by a perspective transform. 
     
     
       6. The lighting apparatus of  claim 1 , wherein the light source is a light emitting diode (LED). 
     
     
       7. The lighting apparatus of  claim 1 , wherein the light source is the exit aperture of an arbitrary lighting apparatus. 
     
     
       8. The lighting apparatus of  claim 1 , wherein the tailored optical surface is a mirror instead of a lens. 
     
     
       9. The lighting apparatus of  claim 1 , wherein an emitting area of the light source is smaller than a surface area of the lens. 
     
     
       10. The lighting apparatus of  claim 1 , wherein the lens projects a polygonal region on a flat projection surface. 
     
     
       11. The lighting apparatus of  claim 1 , wherein the light source has a noncircular boundary. 
     
     
       12. The lighting apparatus of  claim 1 , further comprises an electrical circuit configured to supply an electric power to the light source such that the light source emits the rays of light. 
     
     
       13. The lighting apparatus of  claim 1 , further comprises a housing, wherein the housing is configured to hold the light source and the lens such that an optical axis of the light source and an optical axis of the lens are aligned. 
     
     
       14. The lighting apparatus of  claim 1 , wherein the lens is configured such that the rays from the light source are refracted through an optical surface boundary of the lens to illuminate a target boundary without spill.